Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

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In traditional aircraft wing structural design, the emphasis has been on pursuing the minimum weight or improved performance. The manufacturing complexity or cost assessments are rarely considered because it is usually assumed that the minimum weight design is also the minimum cost design. However, experience from industry has shown that this is not necessarily the case. It has been realised that in the cases where no manufacturing constraints are imposed, the extra machining cost can erode the advantages of the reduced weight. As manufacturing cost includes material cost and machining cost, whilst reducing weight can reduce the material cost, if the manufacturing complexity increases greatly as a result the overall cost may not go down. Indeed, if the manufacturing complexity is not checked, the machining cost could increase by more than the amount by which the material cost reduces. To enable the structural manufacturing complexity to be controlled, manufacturing constraints are established in this thesis and integrated into the optimisation of the aircraft wing structural design. As far as the manufacturing complexity is concerned, attention has been paid to both 3-axis and 5-axis machining. The final designs of optimisations with manufacturing constraints prove the efficiency of these constraints in guiding the design in the manufacturing-feasible direction.

Master of Science

A new economic model for the evaluation of integrated Design, Production, and Logistic Support Systems (DPLSSs) is designed and developed in this thesis. The DPLSS model was created after a survey of Life Cycle Costing (LCC) applications revealed that no models for assessing integrated design, production, and logistic support systems were available. The evaluation technique the model is based on is called Life Cycle Value Assessment (LCVA). LCVA differs from LCC in that it emphasizes consideration of life cycle revenues as well as costs. The system addressed by the DPLSS model has a life cycle which includes product design, production capability design and construction, production, product distribution, logistic system support and maintenance, and system disposal. The baseline production capability assumed when developing the DPLSS model involves batch processing, forming the base material into individual units, and performing detailed processing operations. It has also been assumed that items produced are non-repairable. The DPLSS model facilitates the evaluation of new DPLSSs by leading managers through the new LCVA methodology, A Cost Breakdown Structure (CBS) which is compatible with the DPLSS life cycle has been developed as a basis for the model. This CBS is used to address DPLSSs descriptively and non-natively during LCVA evaluations. A menu-driven computer program has also been developed to implement the DPLSS model on an IBM PC. This program leads users through the new LCVA-based methodology, performs economic and sensitivity analyses on their inputs, and then allows "what-if?-analyses on varying system configurations to be performed. / Master of Science

A common practice in reliability studies is to model the failure process of systems with a single distribution. This thesis investigates this practice for modeling the failure distribution of systems subject to a finite number of independent failure mechanisms experiencing age acceleration. The models of systems during component age acceleration and the models of the residual lives of systems surviving component age acceleration are investigated. The fit of a single distribution to represent the failure time distribution of such systems is investigated for both modeling environments. More importantly, the assumption of time scale compression, and the resulting effect of parameter stability in the single Weibull and lognormal distribution models, is investigated for systems experiencing both differential component age acceleration and uniform component age acceleration. The analysis in this thesis shows that single distribution models are biased when modeling systems with non-identical components. Also, parameter stability in the single distribution models does not occur when the components experience differential age acceleration. The bias in the models leads systems with uniform age acceleration to experience parameter instability because of data dependency due to the bias. / Master of Science

Due to the unusual political and economic ties across the Strait, the trade between Taiwan and Mainland China, as two independent economic entities, can be regarded as special ¡§state-to-state¡¨ trade. Logically, Taiwanese enterprises, which have invested in Mainland China, can also be defined as special Multinational Corporates¡]MNC¡^. The utmost aims of international capital flows include lowering costs and exploiting new marketplaces. The mature industries in developed economies have been losing their competitive advantages in cost and marketing, while the developing economies are usually able to provide those MNCs with more potential markets and lower operation costs. Therefore, the enterprises in developed economies can alternatively keep their competitive edges by making use of cross-border operations and capital flows. Under the frameworks of International Product Life Cycle (IPLC) and the Diamond Model, the study aims to interpret the motivations of the capital flows and the investment location determinations among Taiwan and the economic regions in Mainland China. Want-Want group, denoted as a successful Taiwan firm in Mainland China, enjoys prosperous experiences in that market. The group categorized as food industry, which falls in the mature period of product life cycle in Taiwan. Hence, the study takes it as an example to illustrate the application of the IPLC theory in the Mainland China, and to interpret the investment local determinants by the conditions illustrated by the Diamond Model. The study has scrupulously examinated the history of Want-Want group investing at Taiwan and various economic regions in China. The findings are that when multinational corporations make foreign direct investments, the Product Life Cycle theory and Diamond Model theory can appropriately interpret the motivation and location selection respectively.

Abstract : The use of social media tools to support small and medium-sized enterprises (SME) to support their business activities throughout the product life cycle (PLC) phases represents an interesting opportunity. SMEs operate in very competitive environments, and face significant challenges primarily caused by their size disadvantage. By nature, social media tools and platforms can enable them to overcome some of these challenges, as they are often very inexpensive, familiar and easy to use, allowing them to reach large audiences they would not be able to reach with traditional and expensive marketing initiatives. To provide solutions to this problem, this research identified three main objectives. The first objective was to draw a picture of the existing academic literature on the use of social media tools in the PLC context to better understand how these tools were studied and used in businesses, and for what purpose. Second, this research aimed at understanding how SMEs actually use social media tools to support their different business activities to identify the gap between academic research and actual business practices. Finally, based on the findings highlighted from the previous objectives, this research aimed at developing theory on this topic by proposing a conceptual framework of customer engagement enabled by social media. The conceptual framework aimed at answering general questions that emerged from the initial two objectives: Why do some SMEs use social media to support customer engagement, while others do not? Why do firms use different social media tools to support their customer engagement initiatives? Why does the scope of customer engagement initiatives (i.e., across different PLC phases) vary between SMEs? What are the potential outcomes of conducting customer engagement initiatives for the organizing firms? In order to achieve these research objectives, the methodology employed for this research is threefold. First, a systematic literature review was performed in order to properly understand how the use of social media tools in the PLC context had been studied. The final results consisted of 78 academic articles which were analyzed based on their bibliometric information and their content. Second, in order to draw the contrast between the academic publications and managerial reality of SMEs, six semi-structured interviews were conducted to understand how these firms actually use social media to support different activities in each of the PLC phases. Third, five additional semi-structured interviews were performed to gather a deeper understanding of this phenomenon and generate theory to support the proposed conceptual framework. The conceptual framework focuses on the degree of customer engagement, which is comprised of the scope (PLC phases) of customer engagement and the technology (social media tools) employed to support these initiatives. Two sets of antecedents were examined, firm motivators and firm impediments, as they could both potentially affect the scope and the social media tools used to support customer engagement initiatives. Finally, potential customer engagement outcomes for SMEs developing these initiatives were also examined. The semi-structured interviews lasted approximately 25-35 minutes, and were performed using an interview grid consisting of 24 open-ended questions. The interview grid was developed based on the findings of the systematic literature review, and this qualitative approach allowed for a rich understanding of the interviewed SMEs’ use of social media tools to support and engage customers in their different PLC activities. The main results highlighted by this project demonstrate that this field is relatively recent and sees constant increase in research interest since 2008. However, most of the academic research focuses on the use of social media tools to support innovation activities during the new product development process, while the interviewed firms almost exclusively used the tools to engage customers in the later phases of the PLC, primarily for promotion, customer service support, and business development activities. Interestingly, the interviewed firms highlighted several benefits of using social media tools to engage customers, some of which could help them overcome certain size disadvantages previously mentioned. These firms are in need of further guidelines to properly implement such initiatives and reap the expected benefits. Results suggest that SMEs are far behind both large companies and academic research in their use of social media to engage customers in different business activities. The proposed conceptual framework serves as a great tool to better understand their reality and eventually better support them in their social media and customer engagement efforts. However, this framework needs to be further developed and improved. This research project provides a 360-degree view of the phenomenon of the use of social media to support customer engagement for SMEs, by providing both a thorough systematic review of the academic research and an understanding of the managerial reality of SMEs behind this phenomenon. From this analysis, a conceptual framework is then proposed and serves as a stepping stone for future researchers who are interested in developing theory in this field. / Résumé : L’utilisation des médias sociaux en support aux activités d’affaires dans chaque phase du cycle de vie des produits et services des petites et moyennes entreprises (PME) représente une excellente opportunité pour les entreprises cherchant à se différencier du marché et se rapprocher de leur clientèle. Les PME œuvrent dans des milieux extrêmement compétitifs et doivent faire face à cette concurrence avec des ressources généralement inférieures aux grandes entreprises qui œuvrent dans la même industrie. L’idée d’identifier comment les technologies peuvent soutenir les PME et réduire l’écart qui les sépare de certains joueurs dans leurs milieux respectifs est apparue comme un sujet pertinent, ayant le potentiel d’amener une contribution académique et managériale. Les médias sociaux ont, par leur nature, le potentiel de permettre aux PME de rejoindre les masses, démontrer de la créativité et ainsi être plus compétitifs que jamais. Les médias sociaux s’avèrent d’autant plus pertinents puisqu’ils sont accessibles à relativement moindre coût, nous sommes familiers avec ces outils et ils sont généralement faciles à utiliser. Ils peuvent ainsi permettre aux entreprises d’accomplir des choses que leurs ressources ne pourraient normalement pas leur permettre. Afin de soutenir les PME dans leurs efforts pour réduire cet écart face aux grandes entreprises, ce projet de recherche identifie trois principaux objectifs. Le premier objectif était de dresser un portrait de la littérature scientifique sur l’utilisation des outils de médias sociaux dans le contexte de cycle de vie des produits afin de mieux comprendre comment ces outils ont été étudiés et utilisés en entreprises. En second lieu, cette étude avait comme but de comprendre comment les PME utilisent les médias sociaux pour supporter leurs différentes activités d’entreprises afin d’identifier l’écart entre la littérature scientifique et la réalité de monde des affaires. Finalement, cette recherche vise à développer de la théorie sur ce sujet en proposant un cadre conceptuel sur l’engagement des consommateurs soutenu par les médias sociaux. Le cadre conceptuel a comme objectif de répondre aux questions qui ont émergé en analysant les réponses aux deux premiers objectifs: pourquoi certaines PME utilisent les médias sociaux pour soutenir l’engagement des consommateurs alors que d’autres ne le font pas? Pourquoi les entreprises utilisent-elles différents outils de médias sociaux pour soutenir leurs initiatives d’engagement des consommateurs? Pourquoi est-ce que la portée (différentes phases du cycle de vie des produits) des initiatives d’engagement des consommateurs varie entre les PME? Quels sont les aboutissements potentiels pour une organisation qui met sur pied une initiative d’engagement des consommateurs? Dans le but de répondre à ces objectifs, la méthodologie employée est constituée de trois étapes distinctes. Premièrement, une revue systématique de la littérature a été exécutée afin de comprendre comment l’utilisation des médias sociaux dans le contexte de cycle de vie des produits a été étudiée. 78 articles ont répondu aux critères d’exclusion et ont été analysés afin de faire ressortir des résultats basés sur leur information bibliométrique et leur contenu. Deuxièmement, afin de délimiter l’écart entre les publications académiques et la réalité des PME, six entrevues semi-structurées ont été menées afin de comprendre comment ces entreprises utilisent les médias sociaux pour supporter différentes activités dans chaque phase du cycle de vie des produits. Troisièmement, cinq entrevues semi-structurées supplémentaires ont été menées afin d’obtenir une compréhension plus en profondeur de ce phénomène et ainsi générer de la théorie pour développer davantage le cadre conceptuel proposé. L'accent du cadre conceptuel est le degré d’engagement des consommateurs, qui comprend la portée (phases du cycle de vie des produits) de l’engagement des consommateurs et les technologies (outils de médias sociaux) utilisées pour soutenir ces initiatives. Deux antécédents ont été examinés, soient les motivateurs et les obstacles aux entreprises, puisqu’ils pourraient tous deux potentiellement affecter la portée et les outils de médias sociaux utilisés en soutient aux initiatives d’engagement des consommateurs. Finalement, les aboutissements potentiels à engager les consommateurs pour les PME qui mettent sur pied ce genre d’initiatives sont également examinés. Les entrevues semi-structurées étaient d’une durée d’environ 25 à 35 minutes. Une grille d’entrevue composée de 24 questions ouvertes a été utilisée afin d’orienter les entrevues et collecter des données. Cette grille a été développée en fonction de l’analyse et des résultats provenant de la revue systématique de la littérature. L’approche qualitative de ces entrevues a permis d’obtenir une compréhension en profondeur de l’utilisation des médias sociaux en support à l’engagement des consommateurs dans diverses activités du cycle de vie des produits des PME. Les principaux résultats de ce projet illustrent que ce domaine d’étude est relativement récent et illustrent une constante croissance dans l’intérêt de recherche pour ce sujet de recherche depuis 2008. Cependant, la plupart des recherches académiques mettent l'accent sur l’utilisation des médias sociaux en support aux activités d’innovation lors des phases du processus de développement de nouveaux produits, alors que les entreprises interviewées utilisent presque exclusivement les médias sociaux pour engager les consommateurs à des fins de promotion, service à la clientèle et développement d’affaires lors des dernières phases du cycle de vie des produits. Il est intéressant de noter que les entreprises interviewées ont identifié plusieurs bénéfices à utiliser les médias sociaux afin de surmonter certains désavantages mentionnés ci-dessus. Ces bénéfices potentiels illustrent l’importance pour ces PME de bénéficier de plus amples directives et recommandations afin d’effectivement implanter ces initiatives et de récolter ces bénéfices potentiels. Nos résultats nous ont permis de comprendre que les PME sont en retard sur les grandes entreprises et le milieu académique dans leur utilisation des médias sociaux pour engager les consommateurs dans diverses activités d’entreprises. Le cadre conceptuel proposé est un excellent outil permettant de mieux comprendre la réalité des PME et éventuellement de mieux les supporter dans leur implantation de divers médias sociaux et leurs efforts pour engager des consommateurs. Cependant, ce cadre conceptuel nécessite davantage de recherches afin de le développer davantage et l’améliorer. Cette recherche se différencie des autres recherches dans ce domaine en fournissant une vue globale de ce phénomène, soit une rigoureuse revue systématique de la littérature académique, ainsi qu’une analyse de la réalité pratique des PME. De cette analyse, un cadre conceptuel est proposé et sert de fondement pour les futurs chercheurs qui souhaitent développer de la théorie reliée à ce domaine d’étude.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management